This could be either (1/3)x-6=24 or (1/3)x+6=24.
If the first: (1/3)x=30 so x=90; if the second: (1/3)x=18 so x=54.
It could also be 1/(3x)-6=24, so 1/(3x)=30, 3x=1/30, so x=1/90; or 1/(3x)+6=24, 1/(3x)=18, 3x=1/18 so x=1/54. These last two answers seem unlikely so x=90 or 54. I think it's probably x=90 so the original question was (1/3)x-6=24.